【摘要】 提出了一种基于CPLD的全双工异步串行口的扩展设计方案,其功能是通过并行口实现串行口扩展,讨论了此扩展口通信过程中握手信号的变化规则.根据本方案,设计了一个能扩展三个全双工异步串行口的实例,实现了串行异步通信口的扩展,并给出了仿真波形.此扩展串行口的每个子口可同时工作,并且每个子口的波特率可设为不同的值,适用于各个子口同时工作在不同波特率情况下的场合.更多还原

【Abstract】 A design scheme of a pull-duplex extending serial port based on CPLD is presented. This scheme carries out an extending serial port by a parallel port. The Variation rules of the handshaking singnal during serial port communication are discussed. Based on the scheme, we give an example for three asynchronous serial sub-ports to relize the asynchronous serial communication port extending. The simulation results of this pull-duplex extending port are also given. All sub-ports of the serial port work at one time, but the baud rate in each sub-port can be set with a different value. The extending serial port can be used for the situation, which is that all slave-machine works at one time but with different band rate.更多还原